Why the 49ers’ Defense Won’t Skip a Beat With Marques Sigle Out

It's a bummer that he's out, but it isn't detrimental.

Sep 27, 2026; Santa Clara, California, USA; San Francisco 49ers safety Marques Sigle (36) gestures during the fourth quarter against the Arizona Cardinals at Levi's Stadium. Mandatory Credit: Darren Yamashita-Imagn Images | IMAGN IMAGES via Reuters Connect

As sweet as it was for the San Francisco 49ers to defeat the Denver Broncos in Week 4, there was a downside to it.

Starting safety Marques Sigle suffered a high ankle sprain in the game. He’s expected to miss some time, which could be through their Bye Week. Sigle’s injury is a real bummer, as he’s been playing really well this season. 

He’s stepped it up a ton with every facet of his game. He hasn’t been the liability that he was last season, especially in pass coverage. It’s been impressive to see him improve. Even Kyle Shanahan knows it.

“I think he's been playing his ass off in the run and pass game,” said Shanahan. “The way he's filled on some of these tackles, just how solid he's hit people and how quickly he's done it getting up in there.

“I thought he's done it good in the pass game too. He did a lot of good stuff last year, but I think he has taken it to another level, just playing a little bit faster, hesitating less, knowing what he's doing and really playing well before that injury.”

The 49ers will miss seeing Sigle ascend, but it doesn’t mean their defense will see a significant drop-off. In fact, the 49ers won’t skip a beat with Sigle out for a while. 

They have Malik Mustapha, who can fill in perfectly. He’s been doing an excellent job in the limited snaps he’s had in the last few weeks. There’s even a chance that he can be an upgrade from Sigle. 

“Every time he's come in, I think he's played at a high level,” Shanahan said of Mustapha. “I thought he did that yesterday and made one of the biggest plays in the game yesterday on that third-and-five when he broke that pass up. I'm real excited with Malik and how he's looked.”

The only reason Sigle is starting is because Mustapha hurt his hamstring early in training camp. He didn’t return until before the 49ers flew out to Australia.

Credit to Sigle for performing well and ascending, but he isn’t an impactful player yet. Mustapha has demonstrated more of an impact so far, especially in the last game when he had a pass breakup on third down, as Shanahan alluded to. 

If Mustapha has more plays like that with Sigle, he most likely will hold onto the starting job.

---

Follow Jose on X (Twitter) @JS3sanchezz and his YouTube channel to interact with him on the 49ers and more.